Changes in the abundance and structure of bacterial communities in the greenhouse tomato cultivation system under long-term fertilization treatments

- Impacts of 11-year fertilization practices on greenhouse soils are investigated.
- The C/N ratio of fertilizers input influences bacterial community structures.
- Balanced fertilization with the C/N ratio of 25-35:1 improves soil fertility best.
- Nappropriate input of nitrogen tends to introduce pathogens and suppress nitrifier.

The influence of fertilization on soil microenvironments is one of the frontier topics in agricultural science. Despite the numerous relevant studies on cropland, little is known about the effect of fertilization treatments, especially long-term treatments, on greenhouse vegetable cultivation systems. In this study, the greenhouse tomato (Solanum lycopersicum L.) cultivating soils in Shouguang, Shandong province, China, subjected to different fertilization treatments over a 11-year period were examined. The abundance and structure of the bacterial communities, particularly the pathogenic and beneficial communities, were analyzed. The results revealed that the carbon-nitrogen (C/N) ratio of the fertilizer input played crucial roles in soil fertility improvement. The treatment of “conventional chemical N and straw” with a C/N ratio of 33:1 presented the highest increase in soil nutrition and microbial activities, when compared with the treatments of “conventional chemical N” and “organic amendment only”, indicating the structural rationality of the microbial community. Disproportionate input of nitrogen tended to introduce soil-borne pathogens such as Luteimonas and suppress beneficial microorganisms such as nitrifier. Studies on the below-ground changes of soil could help to develop an optimized microbial community structure and an agro-ecosystem with better sustainability.

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